1. Field of the Invention
Present invention is directed to a word processing system and more particularly to a printer and encoding unit capable of handling a large number of characters such as the symbols of the Japanese or Chinese language.
2. Description of the Prior Art
The Japanese written language has been basically derived from Kanji Chinese characters and today three forms of writing are frequently utilized in Japan. These include a normal written form of a Japanese like alphabet having approximately 46 simple symbols and 25 variations called Hiragana, supplementing the Hiragana form of printing is another written character system called Katakana which is basically a phonetic forming of words in writing. Both of these types of Kana have evolved from the basic Kanji symbols and now exist as separate symbols themselves. With certain exceptions, the use of Katakana in the Japanese written writing system is limited to those names or words that are foreign in origin. In modern day Japan, there has been increasing trends of using foreign words.
The Kanji characters are relatively intricate and are generally used to convey meanings as opposed to being used merely as phonetic symbols. Since each symbol can convey a word or a phrase to the reader, a person versed in the Japanese written language must have a knowledge of symbols running into the thousands. Approximately a minimum of 2,000 Kanji characters are required as a vocabulary of written characters for a printer or typewriter. The printer also must include the Kana and especially the Katakana symbols since a written document in Japanese will integrate all three styles of writing.
As can be readily appreciated, the net effect of this relatively sophisticated and complex form of writing is to create relatively complex problems in providing a modern day word processing system. The mere number of characters that must be provided by individual font type creates storage, retrieval, alignment and encoding problems. In addition to the Japanese characters, there is a requirement for additional symbols such as numbers, etc., so that the resultant total number of individual characters required approaches 2,200.
To date, an economical Japanese character word processing system is not available. Japanese character typewriters are known and generally utilized a movable tray of type font that is individually selected in a panographic manner with a selecting stylus. The large number of characters required in the Japanese language has necessitated a relatively complicated mechanical linkage system which is manually operated by the typist. In an attempt to automize a Japanese character typewriter, there has been suggestions to use an impact style printer which employs individual characters on a character drum. However, problems exist with the use of a character drum relating to the complicated control mechanism required for a drum containing such a large number of characters. In addition there are always the problems of obtaining high printing speed with sufficiently high quality print.
At the present date, there are no known serial Japanese character printers suitable for the commercial market with satisfactory print quality and printing speed, nor at the present time has there been provided a sophisticated word processing system to meet the increasing demands of the scientific and industrial fields.
As can be appreciated, serial printers are available in English, which by comparison requires only a limited number of character symbols to adequately convey the written English language. For example, high quality print has been obtained with word processing systems in the United States which includes a serial printer having a character ball, drum or character wheel such as disclosed in U.S. Pat. No. 3,913,722. Other examples of typewriters and printers can be found in U.S. Pat. No. 3,904,015, U.S. Pat. No. 3,890,894, U.S. Pat. No. 3,892,303 and U.S. Pat. No. 3,554,347.
In summary, word processing systems providing a high-speed, high quality print has been achieved with printers having a limited character writing system. To date, there are no known serial Kanji printers having a suitable cost for the commercial market with satisfactory printing quality and printing speed. As a result, when it is required to print Japanese characters, generally, Hiragana and Katakana must be resorted to and Kanji will only be utilized where necessary with a resulting increase in cost reduction and speed. Obviously this limitation seriously impedes the utilization of an intricate and sophisticated written language system in the modern commercial world.